<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<iframe src="http://b.xxx.com:8080/admin/form/designer/designer.html" style="width: 100%;height: 800px"></iframe>
</body>
</html>
<script >
    document.domain="xxx.com";
</script>